Xolair (Omalizumab) Injection: Uses, Dosing, Side effects, MOA, Price

Xolair (Omalizumab)

Xolair (Omalizumab) injection has been approved by the FDA since 2003 for the treatment of eosinophilic asthma, hives, and nasal polyps.

It is a biological drug that is prepared by recombinant DNA technology. It inhibits the binding of IgE to its receptors inhibiting diseases mediated by IgE.

Hence, it is used in the treatment of various allergic conditions like allergic asthma, hives or urticaria, and nasal polyps.

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Omalizumab (Xolair) Injection Uses (Indications):

Omalizumab (Xolair) is FDA approved for the treatment of the following conditions [Ref]:

  • Asthma:

Xolair is indicated for the treatment of moderate to severe allergic asthma in children older than 6 years of age and adults who have:

  1. a positive skin allergen test,
  2. those who have a positive in vitro reaction to perennial aeroallergens, and
  3. individuals whose asthma is inadequately controlled with inhaled corticosteroids

In such patients, Xolair (Omalizumab) may reduce the frequency of exacerbations, however, it is not recommended in the acute settings when the patient has severe shortness of breath and bronchospasm.

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  • Nasal polyps:

Xolair (Omalizumab) is also used to treat individuals who are at least 18 years of age with nasal polyps. It is usually indicated in such patients as an add-on to intranasal corticosteroids.

  • Chronic Idiopathic Urticaria:

Omalizumab (Xolair) is also used in individuals with chronic idiopathic urticaria who are at least 12 years of age.

It is not indicated for hives or urticaria that have a known underlying cause such as drugs and food allergies.

In summary:

Xolair (Omalizumab) Indications


Age limit

Asthma6 years and above
Nasal polyps18 years and above
Chronic idiopathic urticaria12 years and above

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Omalizumab (Xolair) Dosage:

Xolair is available as:

  • Prefilled Pen, and 
  • Prefilled syringe

It is available as 75 mg and 150 mg injections for subcutaneous use. For higher doses, two injections can be mixed and administered.

Upto150 mg dose can be administered as a single injection, 225 – 300 as two separate injections, 375 – 450 as three separate injections, and 525 – 600 as four separate injections.

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Xolair (Omalizumab) Dose in Asthma and nasal polyps:

Xolair dosing in asthma and nasal polyps is dependent on baseline body weight and IgE levels. However, the dose is not dependent on IgE levels when treating chronic idiopathic urticaria.

In addition, IgE levels do not need to be repeated to readjust the dose. On the other hand, the dose may need to be adjusted when significant weight changes are observed.

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If there is an interruption in the dose, the time duration of treatment interruption should be checked. If it is less than one year, the dose should be based on the initial IgE level on which treatment was initiated.

However, if more than one year of treatment interruption has occurred, the dose of Xolair should be adjusted based on fresh IgE levels and body weight.

Xolair Dosing in moderate to severe asthma in adults or children older than 12 years of age:

The usual recommended dose varies from 75 mg to 375 mg every two to four weeks. The dose is based on the serum IgE levels and body weight as given in the table below:

Xolair Dose in Asthma (for 12 years and older) – Dosing Frequency: Every 4 weekly except where mentioned.

Ig E levelsBody weightXolair Dose
30 – 100Weight <90 kgs150 mg
Weight >90 kgs300 mg
101 – 200Weight <90 kgs300 mg
Weight >90 kgs225 mg every 2 weekly
201 – 300Weight 30 – 60 kgs300 mg
Weight 61 – 90 kgs225 mg every two weekly
Weight >90 kgs300 mg every two weekly

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Xolair Injection Dose based on serum IgE levels: 2-weekly dose administration:

Xolair Dose in Asthma (for 12 years and older) – Dosing Frequency: Every 2 weekly

Ig E levelsBody weightDose
301 – 400Weight 30 – 70 kgs225 mg
Weight 70 – 90 kgs300 mg
Weight > 90Insufficient data
401 – 500Weight 30 – 70 kgs300
Weight 70 – 90 kgs375
Weight > 90Insufficient data
501 – 600Weight 30 – 60 kgs300
Weight 60 – 70 kgs375
Weight >70 kgsInsufficient data
601 – 70030 – 60 kgs375 mg
>60 kgsInsufficient data

Xolair (Omalizumab) Dose in children 6 -12 years of age:

In children, the dose of Xolair is based on the pretreatment body weight and IgE levels.

The manufacturer’s dosing guide is presented here in the table below:

Xolair Dose in Asthma (for children 6 – 12 years of age) – Dosing Frequency: Every 4 weekly

Ig E levelsBody weightXolair Dose
30 – 100Weight 20 -40 kgs75 mg
Weight 40 -90 kgs150 mg
Weight 90 – 150 kgs300
101 – 200Weight 20 – 40 kgs150 mg
Weight 40 – 90 kgs300 mg
Weight 90 – 125 kgs225 mg every 2 weekly
Weight 125 – 150 kgs300 mg every 2 weekly
201 – 300Weight 20 – 30 kgs150 mg
Weight 30 -40 kgs225 mg
Weight 40 – 60 kgs300 mg
Weight 60 – 90 kgs225 mg every 2 weekly
Weight 90 – 125 kgs300 mg every 2 weekly
Weight 125 to 150 kgs375 mg every two weekly
301 – 400Weight 20 -30 kgs225 mg
Weight 30 – 40 kgs300 mg
Weight 40 – 70 kgs225 mg every 2 weekly
Weight 70 – 90 kgs300 mg every 2 weekly
Weight >90 kgsInsufficient data
401 – 500Weight 20 – 25 kgs225 mg
Weight 25 – 30 kgs300 mg
Weight 30 – 50 kgs225 mg every 2 weekly
Weight 50 to 70 kgs300 mg every 2 weekly
Weight 70 – 90 kgs375 mg every 2 weeks
Weight >90 kgsInsufficient data
501 – 600Weight 20 – 30 kgs300 mg
Weight 30 – 40 kgs225 mg  every two weekly
Weight 40 – 60 kgs300 mg every 2 weekly
Weight 60 – 70 kgs375 mg every 2 weekly
Weight 70 kgsInsufficient data
601 – 700Weight 20 – 25 kgs300 mg
Weight 25 – 40 kgs225 mg every 2 weekly
Weight 40 -50 kgs300 mg every 2 weekly
Weight 50 – 60 kgs375 mg every 2 weekly
Weight >60 kgsInsufficient data

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Xolair Dose in Children: Frequency every two weekly:

Xolair Dose in Asthma (for children 6 – 12 years of age) – Dosing Frequency: Every 4 weekly

Ig E levels

Body weight

Xolair Dose

701 -800Weight 20 -30 kgs225 mg
Weight 30 -40 kgs300 mg
Weight 40 – 50 kgs375
Weight >50 kgsInsufficient data
801 – 900Weight 20 – 30 kgs225 mg
Weight 30 – 40 kgs300 mg
Weight 40 – 50 kgs375 mg
Weight > 50 kgsInsufficient data
901 – 1000Weight 20 – 25 kgs225 mg
Weight 25 -30 kgs300 mg
Weight 30 – 40 kgs375 mg
Weight >40 kgsInsufficient data
1001 – 1100Weight 20 -25 kgs225 mg
Weight 25 – 30 kgs300 mg
Weight 30 – 40 kgs375 mg
Weight >40 kgsInsufficient data
1101 -1200Weight 20 – 30 kgs300 mg
Weight > 30 kgsInsufficient data
1201 – 1300Weight 20 – 25 kgs300 mg
Weight 25 – 30 kgs375 mg
Weight > 30 kgsInsufficient data

Xolair (Omalizumab) dose for nasal polyps:

Xolair dose for nasal polyps is also based on body weight and IgE levels. The following screenshot has been taken from the Xolair FDA prescribing information package insert. It can be used to estimate the dose of Xolair in patients with nasal polyps:

Xolair (Omalizumab) Injection dose for nasal polyps
Xolair (Omalizumab) Injection dose in patients with nasal polyps

The duration of treatment is decided based on the severity of symptoms and clinical improvement.

Xolair dose in the treatment of patients with chronic idiopathic urticaria (CIU):

Xolair (Omalizumab) therapy in the treatment of chronic idiopathic urticaria is not based on serum or total IgE levels.

It is administered in a dose of 150 to 300 mg administered every 2 to 4 weeks. The duration of treatment should be based on the severity of symptoms and clinical improvement.

Patients should be assessed periodically to assess the need for continued therapy or not.

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Omalizumab (Xolair) Dose in Kidney and Liver Diseases:

The manufacturer has not recommended any dosage adjustments in patients who have underlying liver or kidney diseases.

Omalizumab (Xolair) Dose in Pregnancy and breastfeeding:

Xolair has been labeled as “Pregnancy Risk Category B”. Since it is an IgG antibody, it can cross the placental barrier and human breast milk.

Xolair use in early pregnancy has resulted in premature births, low birth weight, and minor congenital defects.

GINA guidelines recommend controlling asthma before planning pregnancy as uncontrolled asthma may negatively affect pregnancy.

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Omalizumab Drug Interactions:

The manufacturer has not recommended any adjustments in the dose when Xolair is administered with other concomitant drugs.

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Adasuve (Loxapine) is inhaled drug that should be avoided in patients on Xolair treatment.

Omalizumab (Xolair) Contraindications:

Severe hypersensitivity reaction is the only contraindication to the use of Xolair (Omalizumab) injection.

It should be avoided in patients who are allergic to the drug or any of its components.

Allergic reactions may be severe and result in facial swelling, hypotension, and bronchospasm. The first dose should always be administered in a hospital setting where measures to resuscitate the patient are adequate.

0.1 – 0.2% of the patients who have been on Xolair injection have been reported to have developed severe hypersensitivity reactions and anaphylaxis.

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Omalizumab (Xolair) Warnings & Precautions:

Risk of Cancer:

Xolair has been associated with an increased risk of certain cancers. The risk is estimated to be around 0.5% of the exposed individuals.

Commonly reported cancers in patients exposed to Xolair include:

  • Breast cancer
  • Melanoma and non-melanoma skin cancer
  • Prostate cancer, and
  • parotid cancer

Xolair use in the treatment of acute exacerbations of asthma:

Xolair should not be used to treat acute bronchospasms as in acute exacerbations of asthma or in patients with status asthmaticus.

Abrupt withdrawal of corticosteroids:

Corticosteroids should not be stopped or discontinued abruptly in patients with long-standing asthma or those with nasal polyps.

Abrupt withdrawal may cause acute exacerbations of asthma. Even in very stable cases, the treatment should be tapered off gradually. Tapering the dose of corticosteroids should be done after consultation with the primary care physician.

In patients with CIU (chronic idiopathic urticaria), the combined use of Xolair and corticosteroids has not been evaluated.

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Eosinophilic Conditions:

Xolair use has sometimes been associated with serious systemic eosinophilia. Systemic symptoms of eosinophilia may manifest as vasculitis similar to Churgh-Strauss syndrome.

Most patients have underlying undiagnosed Churgh-Strauss syndrome, the symptoms of which become prominent when corticosteroids are tapered off, or especially discontinued abruptly.

Physicians should take notice of the following symptoms when the dose of corticosteroids is being tapered off:

  • Eosinophilia
  • Rash
  • Arthritis
  • new-onset of chest symptoms or worsening of underlying chest symptoms
  • new-onset cardiac symptoms
  • neuropathy

Serum sickness-like syndrome:

Patients have been reported to develop serum sickness-like syndrome after Xolair use. Symptoms may include:

  • fever
  • rash
  • arthralgias

These symptoms develop 1 to 5 days after Xolair injection and the symptoms may recur after subsequent injections.

Skin biopsies of these patients have not been conclusive of type 3 hypersensitivity reaction.

Nevertheless, physicians must stop Xolair treatment if symptoms of fever, rash, and arthralgias develop.

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Parasitic Infections:

Since Xolair (Omalizumab) therapy impair the IgE response which is important in clearing helminthic infections from the body, patients on Xolair treatment may be at increased risk of developing helminthic infections.

If during the treatment, patients develop helminthic infections, treatment should be immediately advised. Follow-up tests should be advised to see whether the infection has cleared or not.

In patients who have persistent stool examination positive for helminthic infections, Xolair treatment may be interrupted.

Patients at risk of having helminthic infections should be screened for helminthic infections before the initiation of Xolair therapy and treated.

Laboratory parameters:

Xolair: IgE complexes form after the treatment. Serum total IgE levels may not reflect the actual levels and should not be used to guide the dose or duration of Xolair therapy.

IgE levels may remain elevated even after one year of the treatment.

Side effects of Xolair:

Side effects of Xolair were generally of mild nature. Important warnings and precautions have been mentioned in the section above.

The following table enlists the common side effects of Xolair (Omalizumab):

Xolair side effectsPercentage of patients in the treatment groupPercentage of patients in the placebo
Leg pain4%2%
Arm pain2%1%

Anaphylaxis and injection site reactions are relatively common in patients on Xolair therapy compared to placebo.

Injection-site reactions may manifest as redness, swelling, bruising, pain, and induration.

In addition, children treated with Xolair injections were more likely to develop bronchitis, nasopharyngitis, otitis, abdominal pain, fever, headache, and urticaria.

Cardiac and cerebrovascular side effects:

The overall incidence of cardiovascular and cerebrovascular events was higher among patients treated with Xolair treatment compared to controls.

The relative incidence per 1000 patients-years was as:

Xolair Serious Adverse eventsIncidence per 1000 patient-years in the Xolair-treated patientsIncidence per 1000 patient-years in the control group
Overall incidence13.48.1
Pulmonary hypertension0.50
PE or thrombosis3.21.5
Unstable angina2.21.4


Antibodies against Xolair have also been reported but their clinical significance is not clear. It is also not clear whether these antibodies affect the efficacy of Xolair therapy or not.

Hair Loss with Xolair (Omalizumab):

People on Xolair treatment have reported hair loss. Although hair loss has been attributed as a side effect, post-marketing reports of hair loss have been documented.


Thrombocytopenia has also been reported in post-marketing reports by patients who were on Xolair treatment.

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Omalizumab (Xolair) Monitoring Parameters:

Monitor the patients for evidence of any hypersensitivity reactions, especially after the first dose.

Patients with asthma should have their pulmonary functions done periodically to see for treatment response.

Monitor all patients for signs and symptoms of infections. Specifically, monitor patients for evidence of parasitic and helminthic infections.

Omalizumab (Xolair) MOA (Mechanism of action:

  • Omalizumab inhibits the binding of IgE to FcεRI that are present on the surface of mast cells, basophils, eosinophils, and dendritic cells.
  • This in turn causes the downregulation of IgE-mediated inflammation as evidenced by a reduction in the number of eosinophils and inflammatory mediators such as IL-4, IL-13, and IL-5.
  • The most recently approved monoclonal antibodies that are used to treat asthma target specific interleukins and are more targeted compared to Omalizumab. For example:
    • Dupixent (Dupilumab) targets IL-4 and IL-13
    • Nucala (Mepolizumab) targets IL-5.


  • Omalizumab is metabolized in the liver and the reticuloendothelial cells.


  • It has a bioavailability of 62% after subcutaneous injection.

Time to peak serum concentration:

  • It takes about a week (7 – 8 days) for the drug to reach its peak serum concentration.

Half-life elimination:

  • Xolair has a half-life of about 26 days.

Omalizumab Brands and Price:

Omalizumab is available by the brand name Xolair.

Xolair is available as a prefilled syringe in doses of 75 mcg and 150 mcg.

Each injection of 75 mcg (0.5 ml) costs:  $ 650 USD

Each injection of 150 mcg (1 ml) costs: $ 1301 USD

The price varies in different countries and may be as low as $ 200 USD.

What do you think?

Written by Dr. Ahmed

I am Dr. Ahmed (MBBS; FCPS Medicine), an Internist and a practicing physician. I am in the medical field for over fifteen years working in one of the busiest hospitals and writing medical posts for over 5 years.

I love my family, my profession, my blog, nature, hiking, and simple life. Read more about me, my family, and my qualifications

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